Background/Purpose:

The pharmacological treatment approach for juvenile idiopathic arthritis (JIA) has changed substantially since the introduction of biologics with nowadays inactive disease as realistic goal. However, inactive disease is still not achieved by all patients. Identifying baseline factors which predict etanercept response could improve treatment strategies.

Methods:

The Arthritis and Biologicals in Children (ABC) register (observational study, ongoing since 1999), includes all Dutch JIA patients who use or previously used biologics. Disease activity variables were retrieved prospectively at start of treatment, after 3 months, and yearly thereafter. Analyzed were all biologic-naive patients who started etanercept before October 2009 (n=262). Drug survival (i.e. median duration from start until first discontinuation due to ineffectiveness or adverse events (AEs)) was estimated with Kaplan-Meier analysis. Excellent response (inactive disease or earlier discontinuation due to disease remission) and poor response (less than 50% improvement from baseline, or earlier discontinuation due to ineffectiveness or intolerance) was evaluated 15 months after initiation of etanercept. A univariate and multivariate logistic regression analysis was performed to identify pre-defined potential baseline predictors for excellent and poor response and for occurrence of AEs.

Conclusion:

In daily practice, etanercept is very effective and well tolerated by patients with JIA. Inactive disease was reached in up to 40% of the patients and was sustained years after initiation of etanercept. Excellent response was associated with baseline low disability and less DMARD use before etanercept. Therefore, the focus should be on strategies with early introduction of etanercept to further improve outcomes for JIA. The role of etanercept for systemic-onset JIA remains debatable. However, etanercept should not be rejected as a therapeutic option for this subtype.